At present, while electric power is smoothly supplied for 24 hours in countries with electric power distribution systems, electric power is still not available in the developing countries of Africa and Asia, and about 25% of the world's population do not have access to electric power.
The developing countries of Africa and Asia, which do not have access to electric power, use kerosene as a major energy source, for example, for brightening the darkness using kerosene lamps instead of electric power.
The use of the kerosene lamp in a closed room not only causes respiratory diseases due to emission of hazardous gas, but also always exposes the user to the risk of fire.
In addition, in low-income developing countries of Africa and Asia, the kerosene lamps cannot be used for a long time because the kerosene price is high, and a portion of money paid for kerosene actually takes away from any income earned.
Therefore, the user brightens the darkness using a candle instead of the kerosene lamp, which is expensive, emits hazardous gas, and brings the risk of fire, but there is a problem in that luminous intensity of a flame is insufficient for the user to use daily by only using the flame of the candle.
The present invention relates to a candle-powered lighting apparatus which is provided with a thermoelectric element, which uses the Seebeck effect, between a heat absorbing plate, which absorbs heat generated by a candle, and a heat radiating plate, which radiates the absorbed heat, generates thermoelectromotive force using a temperature difference between a contact surface with the heat absorbing plate and a contact surface with the heat radiating plate, emits light using a lighting unit by converting the generated thermoelectromotive force into a constant current at direct current voltage, controls an operational state of the lighting unit based on a result of measuring luminous intensity of a flame of the candle and an inclination of the candle or the lighting apparatus, and maintains a constant distance between an uppermost side of the candle and the heat absorbing plate using a distance measurement sensor and a candle moving unit.
Here, the thermoelectric elements collectively refer to elements that use various effects generated by an interaction between heat and electricity, and include a thermistor which is an element having properties of negative resistance temperature coefficients in which electric resistance is reduced as a temperature becomes higher, an element which uses the Seebeck effect that is a phenomenon in which thermoelectromotive force is generated as carriers in the thermoelectric element moves when there is a temperature difference, and an element which uses the Peltier effect that is a phenomenon in which heat is absorbed or generated due to an electric current.
The Seebeck effect, among the above effects, is one of the thermoelectric effects in which a current (thermoelectric current) flows through a circuit when both ends of two types of metallic wires or semiconductors, which are joined together, are maintained at different temperatures, and the configuration will be more specifically described below.
When there is a temperature difference between both ends A and B of a single metallic bar, thermoelectromotive force is generated because of a heat flow between the both ends A and B. Because the thermoelectromotive force varies in accordance with the type of metal, there occurs a difference in thermoelectromotive force at the metallic bar having both ends at which different types of metal A and B are joined, and as a result, an electric current flows.
The thermoelectric power generation using the Seebeck effect of the thermoelectric element has an effect in that electricity may be generated by a very simple method in which the thermoelectric element is provided within a short distance from the heat source.